Description

The
copy-pixels
function copies a rectangular area from one port to another. The
transform
,
mask
,
mask-transform,
compositing-mode
and
shape-mode
from
to-port
's graphics-state are used.

The (
to-x to-y
) is transformed according to
to-port
's transform. When
to-port
's
drawing-mode
is
:quality
the target is generally fully transformed, except that when it copies from a visible window it may generate expose events when copying from an obscured part, and in
drawing-mode
:quality
it ignores the transformation in this case.

If
to-port
's
drawing-mode
is
:compatible
then the image is not scaled or rotated. For more information about
drawing-mode
, see "Drawing mode and anti-aliasing" in the
CAPI User Guide
.

The
to-port
and
from-port
need not be the same depth and can be the same object. The
from-x
and
from-y
values are interpreted as pixel positions in the window coordinates of
from-port
, that is, they are not transformed by
from-port
's transform.

Notes

copy-pixels
can be used to draw to an output-pane inside the
display-callback
of that pane, but it cannot be used to copy from the output-pane inside its
display-callback
(the result of such an operation is not defined).